Unix Toolchain Quickstart

This is a tutorial for using a standard Unix toolchain (make, gcc, etc.) with Maple. It’s intended for C and C++ programmers who want to use libmaple directly.

Requirements

For Windows, you will somehow need to install drivers.

At a minimum, you need:

  • Maple board
  • Mini-B USB cable
  • root (or Administrator) access to your computer.

On Linux and OS X, you need to know how to use bash, and how to edit your .bashrc. Some experience using GCC and make is recommended, but is not required.

Setup

You first need to set up your computer by installing and configuring various things. Don’t fret! We’ve got detailed instructions, just for you.

Come back when you’re ready. We’ll wait.

Test compilation

Test that you’ve installed all the compilation tools correctly by running the following commands in your shell.

Windows users:

  • Don’t type the $‘s, just the parts that come after.
  • First get to libmaple by opening a Git Shell, then running cd libmaple.
  • Always type cs-make instead of make.

Linux and OS X users:

  • Run these from the top-level libmaple directory.
$ cp main.cpp.example main.cpp
$ make clean
$ make

If all goes well, you should see a bunch of output, then something like this:

Final Size:
   text          data     bss     dec     hex filename
  13164          1704     552   15420    3c3c build/maple.elf

Hurray! You’ve just compiled your first program for Maple.

Important: if you’re not using Maple (Maple Mini, etc.), make sure to read the following note before moving on.

You can now move on to uploading a program, or take a quick detour to learn more about the build output.

Note

This tutorial assumes you’re using a Maple. If you’re compiling for another board, you’ll need to set a BOARD environment variable appropriately.

To get a list of values for BOARD, run

$ make list-boards

For example, to compile for Maple Mini:

  • On OS X or Linux, run:

    $ export BOARD=maple_mini
$ make

  • On Windows, set a new environment variable named BOARD to value maple_mini, then open a new Git Shell, and run cd libmaple followed by cs-make as explained above.

You can check that this worked by making sure that the final program file is named build/maple_mini.elf instead of maple.elf:

Final Size:
   text       data     bss     dec     hex filename
  16848       2696     704   20248    4f18 build/maple_mini.elf

Other notes for OS X and Linux:

  • You can also use the following, but you’ll need to write the BOARD=maple_mini part every time you call make (for make install, etc.):

    $ BOARD=maple_mini make

  • To make the board setting permanent, add this line to your .bashrc:

    export BOARD=maple_mini

Warning

You must start from a clean build after each time you change BOARD (advanced users: or MEMORY_TARGET). For example, if you compile a program for Maple, then you want to compile another program for Maple Mini, you must run $ make clean before you compile the second program. If you do not, you will experience strange errors.

Notes about the libmaple build

These are just some miscellaneous notes that are good to know. Feel free to skip reading this section.

  • The dec field at the end of the build output under Final Size: gives the total program size in bytes. The text, data, and bss fields respectively break down the size of the program into code, initialized data, and zero-valued data.
  • The long list of object files above the Final Size shows similar information on a per-file basis. You can use it to help slim down programs that use too much space.
  • build/$BOARD.elf is the final build result (where BOARD is maple, maple_mini, etc. depending on your build).
  • There are other files under build you may be interested in, like disassembly and map files.
  • If you want quicker build times, you should check out our blog post, Making libmaple compile faster.

Upload a program

Let’s blow away the little example program and upload the interactive test session to your Maple. This will let you interact with the Maple over a USB serial port.

  • Linux: you need udev rules set up as described in the setup doc.
  • Windows: you need to somehow install drivers.
  • OS X: everything Just Works for you. Aren’t you special?

Plug in your Maple using a Mini-B USB cable, then run

# Window users: as usual, use cs-make instead of make.

$ cp examples/test-session.cpp main.cpp
$ make clean
$ make
$ make install

A number of things can go wrong at this stage. Simple debugging steps include using perpetual bootloader mode, restarting the Maple a couple times, make clean, etc. If nothing works, the forum is your friend.

Communicate over USB-Serial

Now let’s try out the interactive test session. You need to connect to the board’s serial port device file.

  • Linux: this looks like /dev/ttyACM*.
  • OS X: it looks like /dev/tty.usbmodem*.
  • Windows: it will be COMx, where x is some number.

Try using one of these to find out which it is:

# Linux
$ ls /dev/ttyACM*

# OS X
$ ls /dev/tty.usbmodem*

# Windows, works from libmaple directory
$ python support/scripts/win-list-com-ports.py

To open up a session on Linux or OS X, run

$ screen /dev/ttyXYZ

(On Windows, you will need to use a separate program, such as PuTTY.)

screen will present you an empty terminal. Your board is waiting for you to send it a command. Type h to print a list of commands; type any command’s letter to run it.

Example output (for Maple):

> u
Hello World!
> b
Board information
=================
* Clock speed (MHz): 72
* BOARD_LED_PIN: 13
* BOARD_BUTTON_PIN: 38
* GPIO information (BOARD_NR_GPIO_PINS = 44):
        ADC pins (15): 0, 1, 2, 3, 10, 11, 12, 15, 16, 17, 18, 19, 20, 27, 28
        PWM pins (15): 0, 1, 2, 3, 5, 6, 7, 8, 9, 11, 12, 14, 24, 27, 28
        Used pins (7): 13, 38, 39, 40, 41, 42, 43``

To exit the screen session, type C-a k (control-a k) on Linux, or C-a C-\ (Control-a, followed by Control-backslash) on OS X, and type y when prompted if you’re sure.

Note

Using screen sometimes messes up your terminal session on OS X. If your shell starts acting funny after you exit screen, you should be able to fix it with

$ reset && clear

If that doesn’t work, just close the Terminal window and open up a new one.

Start your own project

So everything worked, and you want to start your own project? Great! There are two ways to go about it.

If your project is small, all you have to do is replace ~/libmaple/main.cpp with your own code, and you’re free to use make and make install in the same way you did when you first uploaded a program.

If you have a more complicated project, with its own Makefile and multiple source files, or if you’re using an IDE that creates its own Makefile, you’ll probably want to load libmaple from an archive (a build-time library, not a DLL).

To create an archive, use the library Makefile target:

$ cd ~/libmaple
$ make library

This will produce a build-time library in the file ~/libmaple/build/libmaple.a. To use it, make sure that you link against that library, and that the libmaple sources are in your include path.

There is also a page on starting a project with the Unix toolchain on the LeafLabs wiki that you may find useful.

Get updates

We update libmaple fairly frequently with bugfixes and other improvements. In order get access to these in your local copy of the repository, you should periodically update it with:

$ cd ~/libmaple
$ git pull

We do our best to keep the master libmaple branch on GitHub free from broken or half-finished code, so don’t be too scared running the latest and greatest. If you do, please report any bugs or regressions!

Our blog is the place to watch for major releases; an RSS feed is available.

You can sign up for a free GitHub account and watch libmaple to receive notifications about bleeding-edge development.

(Optional) Upload/Debug with JTAG/SWD

Advanced users will wish to use a JTAG (or SWD) dongle for uploading and debugging their programs. A big advantage to this approach is that it lets you use GDB to single-step through your code, inspect variables, etc.

You can build your projects for JTAG or SWD upload with the jtag Makefile target. That is, instead of compiling with make, compile with

# (This is equivalent to $ MEMORY_TARGET=jtag make)
$ make jtag

Then use your favorite JTAG/SWD dongle and driver software to upload the resulting program. An ELF suitable for upload is in build/$BOARD.elf; the raw binary you can copy directly to address 0x0 is build/$BOARD.bin.

Warning

Uploading code built with the jtag target will overwrite the bootloader. This is a good thing – since you’re using another upload method, this lets you use the Flash and RAM the bootloader ordinarily reserves for itself. You can always reflash the bootloader later.

While LeafLabs doesn’t officially support any particular way of using JTAG with Maple, there is a JTAG How-To on the LeafLabs wiki that you may find useful.

Go forth exuberantly!

Let us know what you come up with! Mention @leaflabs on Twitter, post in the forum, join the the #leafblowers IRC channel on freenode, whatever. We love projects!